High viscosity flotation and damping fluid



3,076,765 HIGH VISCOSITY FLOTATION AND DAMPING FLUKE) Fred W. West, Paterson, Raymond J. Sam, Bloomfield, and Kenneth J. Reilly, Jersey City, N.J., assignors, by mesne assignments, to Minnesota Mining and Mannfacturing Company, St. Paul, Minn, a corporation of elaware No Drawing. Original application Feb. 15, 1957, Ser. No.

640,305. Divided and this application Dec. 11, 15 57, Ser. No. 706,533

4 Claims. (Cl. 252-78) This invention relates to a high viscosity material and to a method for the preparation thereof. In one aspect, this invention relates to a flotation agent for reducing frictional losses in instruments and machines. Another aspect of this invention relates to a damping agent for reducing impact and vibration damage and offers viscous nonelastic restraint to moving parts within a gyro. Another aspect of this invention relates to a halogenated, highly viscous material having high density and high shear stability. Still another aspect of this invention relates to a perchlo-rofluorinated damping and flotation agent for gyro mechanisms.

meats demanded for a material of this type. Typical Other instruments such as the bi-Inetallic dial type ther mometers and chemical seal pulsation dampeners have also indicated a need for a highly viscous material which meets most of the specifications mentioned above.

It is, therefore, an object of the present invention to provide a material having a high viscosity, a low clear point and a high density at elevated temperatures and to provide a method for the preparation thereof.

Another object of this invention is to provide a non corrosive, thermally stable perchlorofiuorinated olefin polymer suitable for use as a damping and flotation fluid. Another objectof this invention is to provide a perchlorofluorinated olefin polymer having a maximum clear point not in excess of 155 F.

Another object of this invention is to provide a low molecular weight percholorofluorinated olefin polymer 3 ,070,705 Patented Feb. 5, 19 53 agent having the above properties.

According to this invention a low molecular weight chlorotriflucroethylene polymer having a melting point between about 140 F. and about 250 F. (ball and ring) is dissolved in a solvent, the temperature of the solution is lowered, the insolubles are removed from the solution leaving a filtrate and the soluble polymer product is re- Which is recovered from the filtrate has a cloud point between about 100 F. and about 215 F. and a viscosity in excess of 200 centistokes at 210 F. This soluble wax product may be used directly as, for example, a specification gyro fluid, or it may be blended with a low molecular weight perhalogenated olefin polymer melting between about F. and about 140 F. to obtain a product having the desired viscosity, density, cloud point and other requirements mentioned above.

The low molecular weight polymeric starting material of the present invention is the homopolymer of chlorotrifluoroethylene which melts at a temperature between about 140 F. and about 250 F. and which has the following formula wherein x is an integer between 10 and and Z and Y are selected from the group consisting of the halogens e) and a perhalo- The preferred chlorotrifluoroethylene polymer is the telomer of chlorotrifluoroethylene wherein Y and Z are normally gaseous halogen atoms (chlorine and fluorine) such as, for example, the telogen prepared from the reaction of chlorotrifluoroethylene with sulfuryl chloride, which telomer has a melting point between about 200 F. and about 235 F. (ball and ring). The preparation of this telomer is given in US. Patent No. 2,770,659.

Other suitable starting materials include the telomer's of chlorotrifluoroethylene with halogens and aliphatic perfluoroethylene and the corresponding telogen in the presence of a peroxy compound. More specific details of the preparations are found in copending applications of William S. Barnhart, Serial No. 347,186 (filed April 6, 1953 now Patent No. 2,875,253) and Serial No. 452,708 (filed August 27, 1954, and now abandoned).

In the process of this invention the chlorotrifluoroethylene polymer is dissolved in a suitable solvent such as an aliphatic alcohol, ketone, ether, ester or halocarbon or an aromatic alcohol, ketone,-ether, ester or hydrocarbon. Examples of suitable solvents used in this invention include Cellosolve, dioxane, methyl phenyl ether, ethyl ether, ethyl phenyl ether, acetone, methyl ethyl ketonc, acetophenone, isopropyl alcohol, diacetone alcohol, mineral spirits, methyl alcohol, benzyl alcohol, ethyl alcohol, ethyl acetate, methyl propionate, ethyl benzoate, carbon tetrachloride, trichloroethylene, chloroform, the Freons, toluene, xylene, etc., and mixtures of these solvents. The polychlorotritluoroethylene is melted before it is admixed with the solvent.

Solvent to polymer ratios employed in this process can be varied between about 0.511 and about 20:1, preferably between about 1:1 and about 15:1. The chlorotr'fiuoroethylene polymer is generally dissolved at an elevated temperature surh as for example, in a solvent which is ma'ntained at a t:mpeature of between about 100 F. and about 305 F. or at about the reflux temperature of the solvent. However, it is also with'n the s-ope of this invention to dissolve the polymer or fraction thereof in a solvent at room temperature (75 F.). The preferred method comprises dissolving the polymer in the solvent at a temperature of about below the reflux temperature ofthe solvent but not at a temptrature in excess of 305 F. While the polymer is being admixed with the solvent, it is generally preferred to agita'e the mixture for a period of between about 10 m'nufes to about 10 hours. In most cases the mixture is agitated fl' a period not exceedlng 2 hours. After the polymer is mixed with the solvent for the desired period of time, some insoluble material may still be present. These-insolubles may be removed immediately if so desired.

The temperature of the sclution of polymeric material prepared above at an elevated temperature is then lowered, preferably by allowing it to cool to about room temperature. However, in cases where the solution has been prepared at room temperature, the solution temperature is lowered for example, by a cold bath or by refrigeration usually to a temperature not below -10 C. and preferably not below 10 C. The lowering of the solution temperature results in the precipitation of insoluble materials. The insoluble material is removed as a residue by fiitration, decaniatfon or by any other convenient process or any combination of the above processes and the desirable polymer fraction or product which remains in the filtrate is recovered by evaporating, flashing otf, fractionating, or distilling off'the solvent or by the addition 'of water, if a water-soluble solvent is employed. The water takes up the solvent and can be decanted leaving a soluble polymer product, more specifically, a soluble wax product as the crude product of this invention. The crude soluble wax production is then dried.

When the desired wax product is recovered by the ad dition of water to the filtrate, the volume of water added to the filtrate can vary between about 0.05 and about 2 volumes or more, preferably between about 0.25 and about 1 volume of water per volume of filtrate. The soluble wax product so obtained is then dried toproduce a wax product having a cloud point between about 100 F. and about 215 F. and a viscosity in excess of 200 centistokes at 210 F. If desired, the insoluble material which is removed after the solutiontemperature has been lowered can be reprocessed by redissolving it in a solvent;

cooling the resulting solution; removing the insoluble materials and adding the resulting filtrate containing crude soluble wax product to the first filtrate before removing the solvent.

In one embodiment of the invention, the process is carried out by dissolving a liquid telomer of chlorotrifiuoroethylene, melting between about 200 F. and about 235 F. in an aliphatic water-soluble solvent at the reflux ternperature of the solvent,-or at a'temperature 5 orlO below the reflux temperature of the solvent employed. The solution is agitated at this temperature for a period of not more than 2 hours and then allowed to cool to room temperature. The resulting insoluble maierial, which is precipitated, is removed from the filtrate and Water is added with agitation to the filtrate in a volume of between about 0.25 and about 1 volume of water for each volume of filtrate. After thoroughly mixing, the solid or crude product is al'owed to settle, the liquors are removed and the remaining solvent is pressed from the soluble wax product so formed. The soluble wax product is then dried at a temperature between about 150 F. to about 250 F. fzr a period of from about 1 to about 16 hours under a pressure not in excess of about 300 mm. Hg, preferably not in exczss of 175 mm. Hg.

In a preferred embodiment of the present invention the liquid telomer of chlorotrifiuoroethylene obtained by melt'ng the telomer is dissolved in a suitable solvent such as, for example, a toluene-isopropyl alcohol mixture, at an elevated temperature such as, for example at about 170 F. The solution is agitated for a period of not more than 2 hours and allowed to cool to room temperature. The resulting insoluble material, which precipitates, is removed from the filtrate and the soluble wax product is completely removed from the filtrate by distilling off the solvent.

The soluble wax product of this process, which has a cloud point between about 100 F. and about 215 F., a density between about 1.905 and about 1.930 at 210 F.

and a viscosity between about 205 and about 700 centistckes at 210 F., is sui.'able for direct use as a flotation or damping agent or it can be blended with a lower molecular weight perhalcgenated wax, such as polychlorotrifiuoroethylene wax having a me'ting point between F. and about 140 F. in amounts whizh vary from 'weight percent to about 20 weight percent of the soluble wax product obtained above, preferably between about 40 weight percent to about 65 we'ght percent of soluble wax product obtained above. When the soluble wax product has a cloud point of F. or above, it is usually desirable, in applications for gyro fluids, to blend the extracted wax products with a lower melting perhalogenated wax, melting between about 90 'F. and about F. for example, a polychlorotrifiuoroethylene wax such as Kel-F 40 wax. The preparation of these low molecular weight, low melting polychlorotrifluoroethylene waxes is given in US. Patent No. 2,770,659.

The following examples are offered as a better understanding of the present invention and are not to be construed as unnecessarily limiting thereto.

The following example in Table 11 illustrates the preparation of the final extracted wax product of this inven- 'rial was removed as a residue andthe wax which remained in the filtrate was labeled Soluble Wax #1. The residue was dissolved in the same solvent at F., the resulting solution was then allowed to cool to room temperature and the insoluble material was removed as the residue. The wax which remained in the filtrate was labeled Soluble Wax #2. The first and second filtrates are usually combined before removal of the solvent to obtain the soluble Wax product, however, in the following example the two soluble wax products, which were separated from the filtrate by the addition of water, by decantation of the supernate and drying the product, were treated separately for comparison purposes.

TABLE II Solvent Extraction of Kel-F 200 Wax Amount of Volume Ex. N0. Kel-F 200 Solvent ratio Components of Wax. g. solvent: Kel-F 200 Wax wax 1, 000 Isopropyl alcohol....

1011 1st soluble wax..-. 2nd soluble wax.-. Residue The cloud point was determined by slowly cooling a 15 gram sample of the final extracted wax product in a 25 x 150 mm. glass tube. All cloud points determined on waxes subsequently described were also carried out in this way.

preparation of the soluble wax product when reprocessing the residue is omitted and compares the properties of the product with the residue. In all the examples in Table III the soluble wax product was removed from the filtrate by distilling off the solvent.

TABLE III Amount Volume Yield. Cloud Density. Density, Ex. No. of Kel-F Solvent ratio. Components of Kel-F 200 perpoint. Viscosity, glee. at gJce. at 200 Wax, solvent Wax cent F. cs./ F.

grams wax 2:1 Soluble wax product 13. 118 200. 3/210 Re due 85. 0 219 5:1 Soluble wax product. 27. 4 134 252. 9/210 Resi ue 71. 2 2: 1 Soluble wax product. 48. 8 401. 9/210 Residue 45. 2 5:1 Soluble wax product. 65. 1 Re 25. 1 6 250 Isopropanol- 10:1 Soluble wax produc 39. 5 due s 54. 9 7 250 do 1 Soluble wax produc 45. 7 Residue 48. 4

1 Calculated to be 12.000 ep. at 140 F. or 6.500 cs. at 140 F.

For comparison purposes, Kel-F 200 Wax was tested and had a cloud point of 216 F.; a viscosity of 132.6 centistokes at 266 F. and a viscosity of about 950 centistokes at 210 F. Kel-F wax (polychlorotrifluoroethylene wax having a melting point between about F. and about F.) was also tested and found to have a cloud point of 96 F., a viscosity of 37.97 centistokes at 210 F. and a density of 1.8792 at 210 F. Al-

The examples in Table IV below show additional exeriments on the preparation of the soluble wax product using dilierent solvents from those used in Table 111. In the following examples (#8 through #23) the soluble wax product was separated from the filtrate by distillation. In Example #24 the soluble wax product was recovered by addition of water, decantation of the supernate and 45 subsequent drying of the soluble wax product.

TABLE IV Amount Volume Yield of Cloud Viscosity Density, g./ee. Ex. Solvent ratio, soluble point, No. solvent: wax, 1*.

wax percent 3, Diacetone alcohol 5:1 2 9 9 Cellosolve 5:1 31. 4 180-35 5:1 81. 8 185-90 5:1 60. 4 165-70 5:1 51. 5 160-65 5:1 80.3 185-90 5:1 91. 9 215-20 g 1:1 68. 9 180-85 2:1 79. 0 185-90 4:1 90. 3 182-85 do 5:1 92.5 185-90, 20% toluene in 5:1 47. 3 -50 33%% toluene in i-PrO 5:1 63. 7 -60 40% toluene in i-PrOH. 5:2 70. 3 -65 50% toluene in i-IrOH 5:1 81.8 -75 23- 20% toluene in i-IrOH 5:1 47. 6 145-50 2,518.4 es. or

Isopropanol.

1 The soluble wax produc fluid for gyro mechanisms.

viscosity requirements.

The following examples in Table III illustrate the t was recovered by the addition 01 water, decantation and drying of the wax product.

Examples #25 through #44 in Table V below give the amount of material employed in the preparation of wax blends having the desired properties of the present invention. The extracted wax product was obtained from Kel-F 200 wax as described in the previous examples which employed a single extraction of the Kel-F 200 wax 75 in solution.

TABLE V Soluble Viscosity, es. Density, g./cc. Viscosity, cp.

wax Soluble Kel-F 40 Cloud product wax wax, point, V iscosity obtained product, grams F. cpl F.

from grams 140 F. 210 F. 140 F 160 F. 210 F. 140 F. 160 I 210 F. example 4 46. 8 53. 2 115-20 46. 4 53. 0 120-25 2 61. 1 38. 9 100-05 3 50. 0 44. 0 110-15 1 7 52. 1 47. 9 115-20 24 50. 8 49. 2 115-20 22 42. 2 34. 8 115-20 6 53. 8 40. 2 110-15 1 12. 500/115 0 57. 2 42. 8 115-20 1 10, 500/120 6 66. 6 33. 4 120-25 1 11, 500/120 6 80 20 125-30 1 1, 400/130 6 90 10 135 13 37. 5 62. 130-35 19 80 20 130-35 19 70 125-30 19 60 120-25 23 80 20 130-35 22 80 20 150-55 22 70 30 140-45 1 l. 9075 1 8, 500 22 40 135-40 1 l. 9015 r 6, 200

I Calculated values.

It is to be understood without departing from the scope of this invention that any of the other polychlorotrifluoroethylene waxes melting between about 140 F. and about 250 F. (ball and ring), particularly polychlorotrifluoroethylene wax melting between about 140 F. and about 160 F. (Kel-F 10200 Wax) can be extracted in accordance with the procedure set forth in any of the above examples to produce a Wax product having the above described valuable properties; and that the wax products so produced can be employed per se or they can be blended with any of the perhalogenated waxes which melt between about 90 F. and about 140 -F.

The products of this invention are particularly suited for use as damping and flotation fluids in gyro mechanisms since they meet all of the rigid requirements for gyro fluids. However, in addition to this application, the products of this invention may also be employed as damping fluids or flotation fluids in other applications such as, for example, chemical seal pulsation dampers, bi-metallic dial type thermometers, and other applications which reqiure a highly viscous material which remains clear at low temperatures.

The extracted wax products or their blends may also be used as protective waxes for surfaces subject to corrosion, as packing material around pipe joints, etc. other applications of these products W111 be apparent to those skilled in the art from the accompanying description and properties of these materials.

This invention relates to the extraction and isolation F. and about 250 F.) and an organic solvent for use in a particular application such as, for example,

tween about 90 ticular application such as, for example, as a gyro fluid.

This application is a division of copending United States patent application Serial No. 640,305, filed February 15, 1957.

Having thus described our invention we claim:

1. A damping and flotation fluid for gyro mechanisms and the like having a high viscosity, low clear point and a high density which comprises a homogeneous mixture f (a) between about 5 a melting point F., and (b) between about and about 20 weight percent of a soluble polychlorotrifluoroethylene wax having a cloud point between about F. and about 215 F. and a viscosity between about 205 and about 700'centistokes at 210 F., said soluble polychlorotrifluoroethylene wax being prepared by (l) dissolving a liquid chlorotrifluoroethylene polymer melting between about F. and about 250 F. in an organic solvent selected from hols, ketones, ethers, esters, aliphatic halocarbons and aromatic hydrocarbons maintained at a temperature not in excess of 315 F., (2) lowering the temperature of the resulting solution to about room temperature to form a residue and a filtrate, (3) separating the residue from the filtrate and (4) removing the solvent from the filtrate to recover a soluble polychlorotrifluoroethylene wax product. 2. The damping and flotation fluid of claim 1 in which the preparation of said soluble polychlorotrifiuoroethylene includes isopropanol as said organic solvent.

3. The damping and flotation fluid of claim 1 in which the preparation of said soluble polychlorotrifluoroethylene includes acetone as said organic solvent.

4. The damping and flotation fluid of claim 1 in which the preparation of said soluble polychlorotrifluoroethylene includes toluene as said organic solvent.

References Cited in the file of this patent UNITED STATES PATENTS 2,700,661 Miller Jan. 25, 1955 2,770,659 Barnhart Nov. 13, 1956 2,786,827 Barnhart Mar. 26, 1957 2,806,866 Barnhart Sept. 17, 1957 2,837,580 Barnhart June 3, 1958 OTHER REFERENCES Material Trade Industrial Research flf UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,076,765 February 5, 1963 Fred W West et al6 that error appears in the above numbered pat- It is hereby certified that the said Letters Patent should read as 7 ant requiring correction and corrected below.

Columns 5 and 6,v TABLE IV Exa N0. 21, under the heading "Volume ratio solvent: wax" for "5:2" read 5: l

Signed and sealed this 17th day of September 1963,

ISEAL) Attest: j

DAVID L. LADD ERNEST W. SWIDER Attesting Officer Commissioner of Patents 

1. A DAMPING AND FLOTATION FLUID FOR GYRO MECHANISMS AND THE LIKE HAVING A HIGH VISCOSITY, LOW CLEAR POINT AND A HIGH DENSITY WHICH COMPRISES A HOMOGENEOUS MIXTURE OF (A) BETWEEN ABOUT 5 AND ABOUT 80 WEIGHT PERCENT OF A POLYCHLOROTRIFLUOROETHYLENE WAX HAVING A MELTING POINT BETWEEN ABOUT 90*F. AND ABOUT 140*F., AND (B) BETWEEN ABOUT 95 AND ABOUT 20 WEIGHT PERCENT OF A SOLUBLE POLYCHLOROTRIFLUOROETHYLENE WAX HAVING A CLOUD POINT BETWEEN ABOUT 135*F. AND ABOUT 215*F. AND A VISCOSITY BETWEEN ABOUT 205 AND ABOUT 700 CENTISTOKES AT 210*F., SAID SOLUBLE POLYCHLOROTRIFLUOROETHYLENE WAX BEING PREPARED BY (1) DISSOLVING A LIQUID CHLOROTRIFLUOROETHYLENE POLYMER MELTING BETWEEN ABOUT 140*F. AND ABOUT 250*F. IN AN ORGANIC SOLVENT SELECTED FROM THE GROUP CONSISTING OF ALCOHOLS, KETONES, ETHERS, ESTERS, ALIPHATIC HALOCARBONS AND AROMATIC HYDROCARBONS MAINTAINED AT A TEMPERATURE NOT IN EXCESS OF 315*F., (2) LOWERING THE TEMPERATURE OF THE RESULTING SOLUTION TO ABOUT ROOM TEMPERATURE TO FORM A RESIDUE AND A FILTRATE, (3) SEPARATING THE RESIDUE FROM THE FILTRATE AND (4) REMOVING THE SOLVENT FROM THE FILTRATE TO RECOVER A SOLUBLE POLYCHLOROTRIFLUOROETHYLENE WAX PRODUCT. 